1. Field of the Invention
The invention relates generally to packer devices used within a wellbore.
2. Description of the Related Art
Packer devices are used to establish a fluid seal within a wellbore. Packers are often incorporated into production tubing strings and then used to form a fluid seal between the outside surface of the tubing string and the inner wall of the wellbore. A number of packer designs incorporate an annular elastomeric sealing element which is placed into a set configuration by axially compressing it. The axial compression causes the packer element to be extruded radially outwardly and into sealing contact against the wellbore wall.
Ordinarily, a setting sleeve is used to apply the compression force to the packer element. A body lock ring is often used as a means to trap the setting force and linear travel of the setting sleeve. A body lock ring is a known device that incorporates a split-ring member that travels over the mandrel of the packer as the packer element is being compressed. The mandrel and inside radial surface of the body lock ring have complimentary wicker-type teeth which prevent the body lock ring from traveling back once the packer element is set. Due to the nature of the tooth profile, however, there is always some slight “back travel” in the body lock ring system as the toothed system relaxes. This generally is not a major issue when using elastomer-type resilient packing elements. But when using relatively rigid packer element systems, minor amounts of back travel can allow the element to relax sufficiently to allow fluid leakage past the packer element following setting.